A vacuum insulation material has thermal conductivity eight or more times lower than that of a typical insulation material and thus has attracted attention as a next-generation high efficiency insulation material. However, since the vacuum insulation material is mainly manufactured as a board type under high vacuum conditions, it is difficult to bend the vacuum insulation material.
At a portion that needs bending of an insulation material, it is difficult to use a vacuum insulation material and thus a general insulation material is used together with the vacuum insulation material to complement the vacuum insulation material by filling the corresponding portion with the general insulation material.
Therefore, there is a need for a groove-type vacuum insulation material that can maintain performance of a vacuum insulation material for a long time by minimizing stress to an outer skin material and be easily bent as needed.
FIG. 1 is a side-sectional view of a general vacuum insulation material.
Referring to FIG. 1, a general vacuum insulation material 30 includes a core material 10 formed as a monolithic board and an outer skin material 20 surrounding the core material.
This type of insulation material does not have bending properties and, in order to perform groove-type vacuum insulation, a plurality of vacuum insulation materials 30 is used or the core material 10 is forcibly bent. However, such forcible bending can apply stress to the core material or the outer skin material, thereby deteriorating characteristics of vacuum insulation.
FIG. 2 is a plan view of one example of the conventional vacuum insulation material, which is applied to an insulation space such as a refrigerator.
Referring to FIG. 2, a box-shaped refrigerator case 50 is provided. Thus, a vacuum insulation material needs to surround four sides of the case 50. However, the general insulation material as shown in FIG. 1 cannot be provided in the form of a groove-type vacuum insulation material surrounding the four sides of the case at the same time.
Thus, it is necessary to use four vacuum insulation materials 30a, 30b, 30c, 30d. In this case, however, manufacturing costs increase and it is inconvenient to apply the insulation materials due to an increased number of insulation materials.
In addition, perfect insulation will not be obtained due to a space between the insulation materials at a corner of the case.
To solve these problems, a flexible core material or a monolithic board type core material having grooves to provide flexibility is used.
However, even in these cases, it is difficult to achieve complete bending properties and the outer skin material is likely to be broken.